﻿using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;

namespace GanagroLiteBO
{
   class SortComparer<T> : IComparer<T>
    {
        private ListSortDescriptionCollection m_SortCollection = null;
        private PropertyDescriptor m_PropDesc = null;
        private ListSortDirection m_Direction = ListSortDirection.Ascending;

        public SortComparer(PropertyDescriptor propDesc, ListSortDirection direction)
        {
            m_PropDesc = propDesc;
            m_Direction = direction;
        }

        public SortComparer(ListSortDescriptionCollection sortCollection)
        {
            m_SortCollection = sortCollection;
        }

        #region IComparer<T> Members

        int IComparer<T>.Compare(T x, T y)
        {
            if (m_PropDesc != null) // Simple sort 
            {
                object xValue = m_PropDesc.GetValue(x);
                object yValue = m_PropDesc.GetValue(y);
                return CompareValues(xValue, yValue, m_Direction);
            }
            else if (m_SortCollection != null && m_SortCollection.Count > 0)
            {
                return RecursiveCompareInternal(x, y, 0);
            }
            else return 0;
        }
        #endregion

        private static int CompareValues(object xValue, object yValue, ListSortDirection direction)
        {

            int retValue = 0;
            if (xValue is IComparable) // Can ask the x value
            {
                retValue = ((IComparable)xValue).CompareTo(yValue);
            }
            else if (yValue is IComparable) //Can ask the y value
            {
                retValue = ((IComparable)yValue).CompareTo(xValue);
            }
            else if (!xValue.Equals(yValue)) // not comparable, compare String representations
            {
                retValue = xValue.ToString().CompareTo(yValue.ToString());
            }
            if (direction == ListSortDirection.Ascending)
            {
                return retValue;
            }
            else
            {
                return retValue * -1;
            }
        }

        private int RecursiveCompareInternal(T x, T y, int index)
        {
            if (index >= m_SortCollection.Count)
                return 0; // termination condition

            ListSortDescription listSortDesc = m_SortCollection[index];
            object xValue = listSortDesc.PropertyDescriptor.GetValue(x);
            object yValue = listSortDesc.PropertyDescriptor.GetValue(y);

            int retValue = CompareValues(xValue, yValue, listSortDesc.SortDirection);
            if (retValue == 0)
            {
                return RecursiveCompareInternal(x, y, ++index);
            }
            else
            {
                return retValue;
            }
        }

    }

    public class BindingListView<T> : BindingList<T>, IBindingListView, IRaiseItemChangedEvents
        {
            private bool m_Sorted = false;
            private bool m_Filtered = false;
            private string m_FilterString = null;
            private ListSortDirection m_SortDirection = ListSortDirection.Ascending;
            private PropertyDescriptor m_SortProperty = null;
            private ListSortDescriptionCollection m_SortDescriptions = new ListSortDescriptionCollection();
            private List<T> m_OriginalCollection = new List<T>();

            public BindingListView()
                : base()
            {
            }

            public BindingListView(List<T> list)
                : base(list)
            {
            }

            protected override bool SupportsSearchingCore
            {
                get { return true; }
            }

            protected override int FindCore(PropertyDescriptor property, object key)
            {
                // Simple iteration:
                for (int i = 0; i < Count; i++)
                {
                    T item = this[i];
                    if (property.GetValue(item).Equals(key))
                    {
                        return i;
                    }
                }
                return -1; // Not found

                // Using List.FindIndex:
                //Predicate<T> pred = delegate(T item)
                //{
                //   if (property.GetValue(item).Equals(key))
                //      return true;
                //   else
                //      return false;
                //};
                //List<T> list = Items as List<T>;
                //if (list == null)
                //   return -1;
                //return list.FindIndex(pred);
            }

            protected override bool SupportsSortingCore
            {
                get { return true; }
            }

            protected override bool IsSortedCore
            {
                get { return m_Sorted; }
            }

            protected override ListSortDirection SortDirectionCore
            {
                get { return m_SortDirection; }
            }

            protected override PropertyDescriptor SortPropertyCore
            {
                get { return m_SortProperty; }
            }

            protected override void ApplySortCore(PropertyDescriptor property, ListSortDirection direction)
            {
                m_SortDirection = direction;
                m_SortProperty = property;
                SortComparer<T> comparer = new SortComparer<T>(property, direction);
                ApplySortInternal(comparer);
            }

            private void ApplySortInternal(SortComparer<T> comparer)
            {
                if (m_OriginalCollection.Count == 0)
                {
                    m_OriginalCollection.AddRange(this);
                }
                List<T> listRef = this.Items as List<T>;
                if (listRef == null)
                    return;

                listRef.Sort(comparer);
                m_Sorted = true;
                OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
            }

            protected override void RemoveSortCore()
            {
                if (!m_Sorted)
                    return;

                Clear();
                foreach (T item in m_OriginalCollection)
                {
                    Add(item);
                }
                m_OriginalCollection.Clear();
                m_SortProperty = null;
                m_SortDescriptions = null;
                m_Sorted = false;
            }


            #region IBindingListView Members

            void IBindingListView.ApplySort(ListSortDescriptionCollection sorts)
            {
                m_SortProperty = null;
                m_SortDescriptions = sorts;
                SortComparer<T> comparer = new SortComparer<T>(sorts);
                ApplySortInternal(comparer);
            }

            string IBindingListView.Filter
            {
                get
                {
                    return m_FilterString;
                }
                set
                {
                    m_FilterString = value;
                    m_Filtered = true;
                    UpdateFilter();
                }
            }

            void IBindingListView.RemoveFilter()
            {
                if (!m_Filtered)
                    return;
                m_FilterString = null;
                m_Filtered = false;
                m_Sorted = false;
                m_SortDescriptions = null;
                m_SortProperty = null;
                Clear();
                foreach (T item in m_OriginalCollection)
                {
                    Add(item);
                }
                m_OriginalCollection.Clear();
            }

            ListSortDescriptionCollection IBindingListView.SortDescriptions
            {
                get
                {
                    return m_SortDescriptions;
                }
            }

            bool IBindingListView.SupportsAdvancedSorting
            {
                get
                {
                    return true;
                }
            }

            bool IBindingListView.SupportsFiltering
            {
                get
                {
                    return true;
                }
            }

            #endregion
            protected virtual void UpdateFilter()
            {

                int equalsPos = m_FilterString.IndexOf('=');
                // Get property name
                string propName = m_FilterString.Substring(0, equalsPos).Trim();
                // Get Filter criteria
                string criteria = m_FilterString.Substring(equalsPos + 1, m_FilterString.Length - equalsPos - 1).Trim();
                criteria = criteria.Substring(1, criteria.Length - 2); // string leading and trailing quotes
                // Get a property descriptor for the filter property
                PropertyDescriptor propDesc = TypeDescriptor.GetProperties(typeof(T))[propName];
                if (m_OriginalCollection.Count == 0)
                {
                    m_OriginalCollection.AddRange(this);
                }
                List<T> currentCollection = new List<T>(this);
                Clear();
                foreach (T item in currentCollection)
                {
                    object value = propDesc.GetValue(item);
                    if (value.ToString() == criteria)
                    {
                        Add(item);
                    }
                }

            }

            #region IBindingList overrides

            bool IBindingList.AllowNew
            {
                get
                {
                    return CheckReadOnly();
                }
            }

            bool IBindingList.AllowRemove
            {
                get
                {
                    return CheckReadOnly();
                }
            }

            private bool CheckReadOnly()
            {
                if (m_Sorted || m_Filtered)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
            #endregion

            protected override void InsertItem(int index, T item)
            {
                foreach (PropertyDescriptor propDesc in TypeDescriptor.GetProperties(item))
                {
                    if (propDesc.SupportsChangeEvents)
                    {
                        propDesc.AddValueChanged(item, OnItemChanged);
                    }
                }
                base.InsertItem(index, item);
            }

            protected override void RemoveItem(int index)
            {
                T item = Items[index];
                PropertyDescriptorCollection propDescs = TypeDescriptor.GetProperties(item);
                foreach (PropertyDescriptor propDesc in propDescs)
                {
                    if (propDesc.SupportsChangeEvents)
                    {
                        propDesc.RemoveValueChanged(item, OnItemChanged);
                    }
                }
                base.RemoveItem(index);
            }

            void OnItemChanged(object sender, EventArgs args)
            {
                int index = Items.IndexOf((T)sender);
                OnListChanged(new ListChangedEventArgs(ListChangedType.ItemChanged, index));
            }

            #region IRaiseItemChangedEvents Members

            bool IRaiseItemChangedEvents.RaisesItemChangedEvents
            {
                get { return true; }
            }

            #endregion
        }
}
